This invention relates to novel mixed aliphatic/aromatic hydrocarbon resins, particularly useful for tackifying purposes. Also, this invention relates to a novel process for preparing the hyrdrocarbon resins wherein 5-aryl-2-norbornene is polymerized, optionally with other alkenes, in the presence of a Friedel-Crafts catalyst. Products resulting from hydrogenation of the hydrocarbon resins are also included within the invention.
Polymers produced from norbornene derivatives are well known in the art, and there are many processes known for the preparation of the polymers. Also known is the use of norbornene, and derivatives thereof, as monomers and comonomers in preparing polymeric materials. In general, norbornene, and derivatives thereof, can be polymerized by ring opening metathesis polymerization method (ROMP), or by catalysis method using metallocene or Ziegler-Natta catalysts. Polymers prepared by the ROMP method have unsaturated backbones, and the process involves opening of the strained, unsaturated and bridged 5-member ring of norbornene. Polymers prepared using Ziegler-Natta catalysts are addition polymers that preserve the norbornene structure. Ziegler-Natta catalysts are typically based on titanium compounds, in combination with an organoaluminum co-catalyst such as triethylaluminum.
Copolymers of norbornene, or substituted norbornene, with ethylene, are commercially available, and are primarily used for optical applications such as compact discs. A problem associated with norbornene-ethylene copolymers is that the copolymers are brittle below the glass transition temperature of the copolymers. It is known that the use of 5-aryl-substituted norbornene, such as 5-phenyl-2-norbornene overcomes the problem of brittleness associated with use of norbornene. It is also known that aryl-substituted norbornene, such as 5-phenyl-2-norbornene, can be copolymerized, using either metathesis catalysts such as tungsten halides or metallocene catalysts such as zirconocene, with other cyclic alkenes or ethylene, to provide interpolymers that exhibit satisfactory modulus, optical, impact-resistant and strength properties.
The polymeric products that are known and commercially available are generally high molecular weight polymers, having a Mn molecular weight exceeding 4000, and as such, are not suitable for use as tackifiers. It is generally acknowledged that tackifying resins have number average molecular weights (Mn) in the range of about 100 to about 1500.
The present invention relates to certain mixed aliphatic/aromatic hydrocarbon resins, that are particularly suitable for use as tackifiers. The hydrocarbon resins are homopolymers of 5-aryl-2-norbornene, or interpolymers of 5-aryl-2-norbornene with at least one, or more, other cyclic or acyclic alkene. The aryl group of the 5-aryl-2-norbornene is any aromatic group or substituent having at least 5 carbon atoms preferably from 5 to about 20 carbon atoms. Exemplary aromatic groups or substituents include phenyl, substituted phenyl, indenyl, naphthyl, methylphenyl, ethylphenyl, propylphenyl, dimethylphenyl, n-butylphenyl, trimethylphenyl, t-butylphenyl, substituted indenyl, substituted naphthyl, and the like. The novel hydrocarbon resins are characterized by having, in combination, (a) a softening point ranging from about 50xc2x0 C. to about 150xc2x0 C., (b) a number average molecular weight (Mn) ranging from about 120 to about 1000, (c) a weight average molecular weight (Mw) ranging from about 150 to about 2000, (d) a z-average molecular weight (Mz) ranging from about 150 to about 4000, and (e) a level of aromatic hydrogen ranging from about 8% to about 40% with respect to the total hydrogen determined by 1H NMR.
The novel 5-aryl-2-norbornene homopolymers and interpolymers thereof with at least one, or more, other cyclic or acyclic alkene, may be hydrogenated to produce novel hydrogenated hydrocarbon resins. The hydrogenated resins have all the above-recited characteristics, (a) through (e), of the 5-aryl-2-norbornene homopolymers and interpolymers described above, and are further characterized by having (f) a mixed methylcyclohexane aniline cloud point (MMAP) ranging from about 15xc2x0 C. to about 65xc2x0 C.
The homopolymers of 5-aryl-2 norbornene, and the interpolymers thereof, with at least one, or more, other cyclic or acyclic alkene, and the resins resulting from the hydrogenation of the homopolymers and interpolymers of the 5-aryl-2-norbornene, are useful as tackifiers for non-woven, hot-melt and pressure sensitive adhesive formulations.
The novel process of the invention for producing the novel homopolymers of 5-aryl-2-norbornene, and interpolymers thereof with at least one, or more, other cyclic or acyclic alkene(s), described herein, is comprised as follows. A 5-aryl-2-norbornene, with a cyclic or acyclic alkene where an interpolymer is desired, is polymerized in the presence of a Friedel-Crafts catalyst, such as, for example, aluminum chloride and boron trifluoride, under suitable polymerization conditions.
The present invention relates to certain mixed aliphatic/aromatic hydrocarbon resins, that are particularly suitable for use as tackifiers. The hydrocarbon resins are homopolymers of 5-aryl-2-norbornene, or interpolymers of 5-aryl-2-norbornene with at least one, or more, other cyclic or acyclic alkene. The aryl group of the 5-aryl-2-norbornene is any aromatic group or substituent having at least 5 carbon atoms preferably from 5 to about 20 carbon atoms. Exemplary aromatic groups or substituents include phenyl, substituted phenyl, indenyl, naphthyl, methylphenyl, ethylphenyl, propylphenyl, dimethylphenyl, n-butylphenyl, trimethylphenyl, t-butylphenyl, substituted indenyl, substituted naphthyl, and the like. The novel hydrocarbon resins are characterized by having, in combination, (a) a softening point ranging from about 50xc2x0 C. to about 150xc2x0 C., (b) a number average molecular weight (Mn) ranging from about 120 to about 1000, (c) a weight average molecular weight (Mw) ranging from about 150 to about 2000, (d) a z-average molecular weight (Mz) ranging from about 150 to about 4000, and (e) a level of aromatic hydrogen ranging from about 8% to about 40% with respect to the total hydrogen determined by 1H NMR.
The novel 5-aryl-2-norbornene homopolymers and interpolymers thereof with at least one, or more, other cyclic or acyclic alkene, may be hydrogenated to produce novel hydrogenated hydrocarbon resins. The hydrogenated resins have all the above-recited characteristics, (a) through (e), of the 5-aryl-2-norbornene homopolymers and interpolymers described above, and are further characterized by having (f) a mixed methylcyclohexane aniline cloud point (MMAP) ranging from about 150xc2x0 C. to about 65xc2x0 C.
The homopolymers of 5-aryl-2 norbornene, and the interpolymers thereof, with at least one, or more, other cyclic or acyclic alkene, and the resins resulting from the hydrogenation of the homopolymers and interpolymers of the 5-aryl-2-norbornene, are useful as tackifiers for non-woven, hot-melt and pressure sensitive adhesive formulations.
The novel process of the invention for producing the novel homopolymers of 5-aryl-2-norbornene, and interpolymers thereof with at least one, or more, other cyclic or acyclic alkene(s), described herein, is comprised as follows. A 5-aryl-2-norbornene, with a cyclic or acyclic alkene where an interpolymer is desired, is polymerized in the presence of a Friedel-Crafts catalyst, such as, for example, aluminum chloride and boron trifluoride, under suitable polymerization conditions.
In further detail, the polymerization process may be operated either in a continuous manner, or, in a batch manner, utilizing a nitrogen-flushed, oven-dried round bottom flask equipped with an overhead stirrer and an additional funnel. In the batch process, the flask is charged with the 5-aryl-2-norbornene, and, optionally, the at least one, or more, other cyclic or acyclic alkene, and the desired Friedel-Crafts catalyst to form a mixture. The resultant mixture is stirred and heated at a temperature of at least 50xc2x0 C., for a time sufficient to effect the polymerization reaction. The temperature in the polymerization process ranges from at least 50xc2x0 C. to about 200xc2x0 C., and, preferably, ranges from about 80 to about 140xc2x0 C. The reaction time required for the polymerization process ranges from about one hour to about twenty hours, with a reaction time of about two to about six hours preferred. The reaction time is dependent on type of catalyst used, concentration of catalyst used, and other reaction conditions.
The at least one, or more, other alkene, that may be interpolymerized with the 5-aryl-2-norbornene, to provide the novel hydrocarbon resins, may be any cyclic or acyclic alkene having from about 3 to about 20 carbon atoms. Exemplary of suitable cyclic or acyclic alkenes are cyclopentene, dicyclopentadiene, 1,5-dicyclooctadiene, 3a,4,7,7a-tetrahydro-4,7-methanoindan (THMINA), 5,6-dihydrodicyclopentadiene, pentenes, piperylene, styrene, alpha-methylstyrene, indene, vinyltoluene, and the like.
In the polymerization process of the present invention there is used as the catalyst, any Friedel-Crafts catalyst. A Friedel-Crafts catalyst is well known to be a catalyst that is capable of catalyzing Friedel-Crafts alkylation/acylation reactions, which are the substitution reactions of hydrogens on an aromatic ring by alkyl groups or acyl groups. Exemplary Friedel-Crafts catalysts include any metal halide, such as aluminum chloride, aluminum chloride complex with hydrochloric acid, aluminum bromide, aluminum fluoride, zinc chloride, titanium chloride, tin chloride, and the like; any boron halide such as boron trifluoride ether complex, boron trifluoride phosphoric acid complex, boron trichloride, and the like; any strong acid such as sulfuric acid, phosphoric acid, hydrochloric acid, hydrofluoric acid, and the like. Friedel-Crafts catalysts preferred for use herein include anhydrous aluminum chloride, boron trifluoride ether complex, and the complex of boron trifluoride with phosphoric acid. The amount of Friedel-Crafts catalyst utilized in the polymerization process ranges from about 0.01% to about 20% by weight of the monomer content of the polymerization process, depending upon the temperature of the reaction, and other reaction conditions. Preferably, the amount of Friedel-Crafts catalyst used in the polymerization process ranges from about 0.1 to about 5% by weight of the monomer content.